Derives the allocation of @renderer inside @area if @area were to be renderered in @cell_area.
the #GtkCellAreaContext used to hold sizes for @area.
the #GtkWidget that @area is rendering on
the #GtkCellRenderer to get the allocation for
the whole allocated area for @area in @widget for this row
where to store the allocation for @renderer
3.0
See Implementation
Derives the allocation of @renderer inside @area if @area were to be renderered in @cell_area.